Obsessed - Glossary of Terms: S-Z

Serotonin: A hormone, also called 5-hydroxytryptamine, in the pineal gland, blood platelets, the digestive tract, and the brain. Serotonin acts both as a chemical messenger that transmits nerve signals between nerve cells and that causes blood vessels to narrow.

SSRI: Abbreviation for selective serotonin reuptake inhibitors, commonly prescribed drugs for treating depression. SSRIs affect the chemicals that nerves in the brain use to send messages to one another. These chemical messengers, called neurotransmitters, are released by one nerve and taken up by other nerves. Neurotransmitters that are not taken up by other nerves are taken up by the same nerves that released them. This process is termed "reuptake." SSRIs work by inhibiting the reuptake of serotonin, an action which allows more serotonin to be available to be taken up by other nerves.

Social anxiety disorder (also known as social anxiety or social phobia): excessive social anxiety (anxiety in social situations) causing abnormally considerable distress and impaired ability to function in at least some areas of daily life. The diagnosis can be of a specific disorder (when only some particular situations are feared) or a generalized disorder. Generalized social anxiety disorder typically involves a persistent, intense, and chronic fear of being judged by others and of potentially being embarrassed or humiliated by one's own actions. These fears can be triggered by perceived or actual scrutiny by others. While the fear of social interaction may be recognized by the person as excessive or unreasonable, considerable difficulty can be encountered overcoming it. Approximately 13.3 percent of the general population may meet criteria for social anxiety disorder at some point in their lifetime, according to the highest survey estimate, with the male to female ratio being 1:1.5

Synapse: The point of connection usually between two nerve cells. Specifically, a synapse is a specialized junction at which a nerve cell (a neuron ) communicates with a target cell. The neuron releases a chemical transmitter (a neurotransmitter ) that diffuses across a small gap and activates specific specialized sites called receptors situated on the target cell. The target cell may be another neuron, or a specialized region of a muscle cell or a secretory cell (a cell than can make and secrete a substance). Neurons can also communicate through direct electrical connections (electrical synapses).

Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.

Trichotillomania: Compulsive hair pulling. A disorder characterized by the repeated urge to pull out scalp hair, eyelashes, eyebrows or other body hair. It is believed to be related to obsessive-compulsive disorder. Treatment may include cognitive-behavior therapy and medications such as Prozac.